A year ago, few would have envisioned that Donald Trump would be the leading Republican candidate for president. Nor would many have predicted that Bernie Sanders would look like a serious contender for the Democratic nomination. While the two politicians may differ in the majority of their messages, their views on economic issues are resonating with middle- and lower-class voters on both the right and the left. WGBH All Things Considered host Barbara Howard spoke with Georgetown University visiting professor and labor studies scholar John Russo, who says a populist defection from the Republican and Democratic mainstream has been a long time coming.